Digital cameras are well known. As their cost continues to drop, digital cameras grow in popularity. Digital cameras eliminate the need to have film developed. They also greatly reduce the need to have prints made, since digital pictures can be viewed on a computer monitor or the like. Although the initial cost may be higher, digital cameras have greatly reduced the overall cost of photography.
It has been estimated that about 100 billion photographs are taken each year world-wide. The use of digital cameras is expected to exceed the use of film cameras for the first time in 2004.
Digital cameras have widespread applications. Digital cameras can be used in both amateur and professional photography. They can also be used in various industrial applications, such as machine vision.
One rapidly growing application for digital cameras is their use in cellular telephones. Camera phones outsold other digital cameras for the first time in the last quarter of 2003. Camera phones allow pictures to be quickly and conveniently shared with others. Images can be captured at the spur of the moment and almost instantaneously communicated to other cellular telephone users and to the Internet.
Although such contemporary camera phones have proven generally suitable for their intended purposes, they possess inherent deficiencies that detract from their overall effectiveness and desirability. For example, contemporary digital cameras commonly have features such as variable focus, optical zoom, and image stabilization. However, contemporary camera phones do not have these desirable features. Contemporary variable focus mechanisms, contemporary zoom mechanisms, and contemporary image stabilization systems are simply too bulky for today's compact camera phones.
Contemporary camera phones have fixed focuses. Although a fixed focus is generally adequate under good lighting conditions, a fixed focus does not perform well when lighting is not so good such as in low light conditions. A fixed focus mechanism approximates a pinhole lens to provide sufficient depth of field as to remain in focus, at least to some degree, regardless of the distance between the subject and the camera. However, such a stopped-down lens is undesirably sensitive to ambient lighting conditions. This is because the near pinhole lens of a fixed focus camera does not admit much light. Thus, such fixed focus cameras generally require more light than variable focus cameras.
When there is insufficient ambient lighting, the image tends to appear undesirably dark. In recognizing the limitations of contemporary camera phones using such fixed focus lenses, the prior art has provided flash mechanisms to insure that adequate light is provided. However, cellular telephones use battery power supplies, and thus have limited power available for the use of such flash mechanisms. More frequent used of the flash to take photographs thus results in the need to more frequently charge the camera phone. Of course, frequent recharging is undesirable.
Although contemporary camera phones may have digital zooms, optical zooms are much preferred instead of digital zooms. As those skilled in the art will appreciate, digital zooms rapidly degrade an image as more magnification is employed. With a digital zoom, as the image becomes larger, it pixelates and loses definition. Optical zooms, on the other hand, do not degrade an image in this manner. However, the components of contemporary optical zoom assemblies, such as motors, gears, metal rods, and springs, are too bulky for use in compact camera phones.
One reason why contemporary camera phones lack autofocus and zoom features is because of the way in which contemporary movable lens are mounted. Contemporary movable lens are mounted in lens barrels or similar structures that surround the lens and that are simply to bulky for used in camera phones. Thus, it would be beneficial to provide a method for mounting movables lens that does not require the use of such barrel structures such that autofocus and zoom features can more readily be implemented in camera phones.
Better contemporary cameras have image stabilization. This feature substantially mitigates the undesirable effects of jitter, such as when caused by the inability to hold the camera very still during an exposure. Jitter may also be caused by other factors, such as the normal vibration of a moving vehicle when a photograph is being taken from within the vehicle.
Image stabilization systems move a camera's optics or its image sensor in a manner that tends to compensate for such jitter. However, the mechanisms that effect such movement in contemporary cameras are too bulky to be used in today's compact cellular telephones.
As such, although the prior art has recognized, to a limited extent, the desirability of providing camera phones with variable focus, optical zoom, and image stabilization, the proposed solutions have, to date, been ineffective in providing a satisfactory remedy. Therefore, it is desirable to provide a miniature camera having variable focus, an optical zoom, and/or image stabilization, wherein the camera is suitable for use in small, portable devices such as cellular telephones.